The present invention relates to a device for feeding blanks to a user machine.
For feeding blanks to a user machine, e.g. a packing machine for folding the blanks about respective products, a device is used comprising a feedbox, from one end of which the stacked blanks are withdrawn successively by a withdrawal device cooperating with a conveyor device by which the blanks are fed to a user station.
On known feed devices of the aforementioned type, the withdrawal device normally consists of a carriage moved linearly back and forth along a path substantially perpendicular to the axis of the stack, and supporting a suction sector. The sector is connected angularly to a gear in turn connected to a fixed rack, and is substantially tangent to the output end of the feedbox, so as to adhere by suction to the end blank in the stack and withdraw it from the feedbox by rotating about its axis as the carriage is moved linearly along said path.
At the end of the carriage stroke, the blank is fed to follow-up conveyor means, e.g. rollers, by which it is transferred to the user station.
Though efficient, the above known device presents a major drawback in terms of reliability, due to the relatively severe acceleration and deceleration to which the carriage supporting the suction sector is subjected when applied to user machines operated over and above a given speed in terms of blank throughput.